* Blue Smoke: This usually points to burning oil. The most common causes are worn piston rings, valve stem seals, or a blown head gasket. The smoke will often smell like burning oil.
* White Smoke: This can indicate a few things:
* Burning coolant: If the smoke is thick and white, and smells sweet, it's likely coolant leaking into the cylinders. This could be due to a blown head gasket, cracked cylinder head, or a cracked engine block. You might also notice a loss of coolant.
* Condensation: On cold mornings, particularly in humid climates, you might see some white smoke which is simply condensation from the exhaust system. This is usually temporary and disappears as the engine warms up.
* Black Smoke: This generally means a rich fuel mixture – your engine is getting too much fuel relative to the air. This could be caused by:
* Faulty fuel injectors: Injecting too much fuel into the cylinders.
* Clogged air filter: Restricting airflow to the engine, leading to a richer mixture.
* Problems with the mass airflow sensor (MAF) or throttle position sensor (TPS): These sensors control the fuel/air mixture; if they're malfunctioning, the mixture can become too rich.
* Problems with the PCV valve: A faulty PCV valve can cause excessive crankcase pressure, leading to oil entering the combustion chamber.
In short: Getting a diagnosis requires more information. Note the color of the smoke, the smell, if you're experiencing any other symptoms (loss of coolant, low oil, reduced power), and have a mechanic inspect your vehicle as soon as possible. Ignoring the problem could lead to significant engine damage.
